agora inbox for pgsql-hackers@postgresql.orghelp / color / mirror / Atom feed
[PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState 653+ messages / 5 participants [nested] [flat]
* [PATCH v2] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState @ 2023-02-25 21:39 Andres Freund <andres@anarazel.de> 0 siblings, 0 replies; 653+ messages in thread From: Andres Freund @ 2023-02-25 21:39 UTC (permalink / raw) --- src/include/executor/execExpr.h | 6 +- src/include/nodes/execnodes.h | 1 - src/backend/executor/execExpr.c | 93 +++++++++++++++++---------- src/backend/executor/execExprInterp.c | 22 +++++++ src/backend/executor/execProcnode.c | 5 ++ src/backend/executor/nodeSubplan.c | 30 ++++----- src/backend/jit/llvm/llvmjit_expr.c | 6 ++ src/backend/jit/llvm/llvmjit_types.c | 1 + 8 files changed, 112 insertions(+), 52 deletions(-) diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h index 06c3adc0a19..ca2b7306cd0 100644 --- a/src/include/executor/execExpr.h +++ b/src/include/executor/execExpr.h @@ -158,6 +158,8 @@ typedef enum ExprEvalOp EEOP_PARAM_EXEC, EEOP_PARAM_EXTERN, EEOP_PARAM_CALLBACK, + /* set PARAM_EXEC value */ + EEOP_PARAM_SET, /* return CaseTestExpr value */ EEOP_CASE_TESTVAL, @@ -374,7 +376,7 @@ typedef struct ExprEvalStep ExprEvalRowtypeCache rowcache; } nulltest_row; - /* for EEOP_PARAM_EXEC/EXTERN */ + /* for EEOP_PARAM_EXEC/EXTERN and EEOP_PARAM_SET */ struct { int paramid; /* numeric ID for parameter */ @@ -738,6 +740,8 @@ extern void ExecEvalParamExec(ExprState *state, ExprEvalStep *op, ExprContext *econtext); extern void ExecEvalParamExtern(ExprState *state, ExprEvalStep *op, ExprContext *econtext); +extern void ExecEvalParamSet(ExprState *state, ExprEvalStep *op, + ExprContext *econtext); extern void ExecEvalCurrentOfExpr(ExprState *state, ExprEvalStep *op); extern void ExecEvalNextValueExpr(ExprState *state, ExprEvalStep *op); extern void ExecEvalRowNull(ExprState *state, ExprEvalStep *op, diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index e7eb1e666ff..16e95e4cb48 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -947,7 +947,6 @@ typedef struct SubPlanState struct PlanState *planstate; /* subselect plan's state tree */ struct PlanState *parent; /* parent plan node's state tree */ ExprState *testexpr; /* state of combining expression */ - List *args; /* states of argument expression(s) */ HeapTuple curTuple; /* copy of most recent tuple from subplan */ Datum curArray; /* most recent array from ARRAY() subplan */ /* these are used when hashing the subselect's output: */ diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c index c61f23c6c18..002f2a0091f 100644 --- a/src/backend/executor/execExpr.c +++ b/src/backend/executor/execExpr.c @@ -87,6 +87,9 @@ static void ExecBuildAggTransCall(ExprState *state, AggState *aggstate, FunctionCallInfo fcinfo, AggStatePerTrans pertrans, int transno, int setno, int setoff, bool ishash, bool nullcheck); +static void ExecInitSubPlanExpr(SubPlan *subplan, + ExprState *state, + Datum *resv, bool *resnull); /* @@ -1388,7 +1391,6 @@ ExecInitExprRec(Expr *node, ExprState *state, case T_SubPlan: { SubPlan *subplan = (SubPlan *) node; - SubPlanState *sstate; /* * Real execution of a MULTIEXPR SubPlan has already been @@ -1405,19 +1407,7 @@ ExecInitExprRec(Expr *node, ExprState *state, break; } - if (!state->parent) - elog(ERROR, "SubPlan found with no parent plan"); - - sstate = ExecInitSubPlan(subplan, state->parent); - - /* add SubPlanState nodes to state->parent->subPlan */ - state->parent->subPlan = lappend(state->parent->subPlan, - sstate); - - scratch.opcode = EEOP_SUBPLAN; - scratch.d.subplan.sstate = sstate; - - ExprEvalPushStep(state, &scratch); + ExecInitSubPlanExpr(subplan, state, resv, resnull); break; } @@ -2618,29 +2608,12 @@ ExecPushExprSetupSteps(ExprState *state, ExprSetupInfo *info) foreach(lc, info->multiexpr_subplans) { SubPlan *subplan = (SubPlan *) lfirst(lc); - SubPlanState *sstate; Assert(subplan->subLinkType == MULTIEXPR_SUBLINK); - /* This should match what ExecInitExprRec does for other SubPlans: */ - - if (!state->parent) - elog(ERROR, "SubPlan found with no parent plan"); - - sstate = ExecInitSubPlan(subplan, state->parent); - - /* add SubPlanState nodes to state->parent->subPlan */ - state->parent->subPlan = lappend(state->parent->subPlan, - sstate); - - scratch.opcode = EEOP_SUBPLAN; - scratch.d.subplan.sstate = sstate; - /* The result can be ignored, but we better put it somewhere */ - scratch.resvalue = &state->resvalue; - scratch.resnull = &state->resnull; - - ExprEvalPushStep(state, &scratch); + ExecInitSubPlanExpr(subplan, state, + &state->resvalue, &state->resnull); } } @@ -4040,3 +4013,57 @@ ExecBuildParamSetEqual(TupleDesc desc, return state; } + +static void +ExecInitSubPlanExpr(SubPlan *subplan, + ExprState *state, + Datum *resv, bool *resnull) +{ + ExprEvalStep scratch = {0}; + SubPlanState *sstate; + ListCell *pvar; + ListCell *l; + + if (!state->parent) + elog(ERROR, "SubPlan found with no parent plan"); + + /* + * Generate steps to evaluate input arguments for the subplan. + * + * We evaluate the argument expressions into ExprState's resvalue/resnull, + * and then use PARAM_SET to update the parameter. We do that, instead of + * evaluating directly into the param, to avoid depending on the pointer + * value remaining stable / being included in the generated expression. No + * danger of conflicts with other uses of resvalue/resnull as storing and + * using the value always is in subsequent steps. + * + * Any calculation we have to do can be done in the parent econtext, since + * the Param values don't need to have per-query lifetime. + */ + forboth(l, subplan->parParam, pvar, subplan->args) + { + int paramid = lfirst_int(l); + + ExecInitExprRec(lfirst(pvar), state, + &state->resvalue, &state->resnull); + + scratch.opcode = EEOP_PARAM_SET; + scratch.d.param.paramid = paramid; + /* type isn't needed, but an old value could be confusing */ + scratch.d.param.paramtype = InvalidOid; + ExprEvalPushStep(state, &scratch); + } + + sstate = ExecInitSubPlan(subplan, state->parent); + + /* add SubPlanState nodes to state->parent->subPlan */ + state->parent->subPlan = lappend(state->parent->subPlan, + sstate); + + scratch.opcode = EEOP_SUBPLAN; + scratch.resvalue = resv; + scratch.resnull = resnull; + scratch.d.subplan.sstate = sstate; + + ExprEvalPushStep(state, &scratch); +} diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c index 19351fe34bf..3cab8a5cdae 100644 --- a/src/backend/executor/execExprInterp.c +++ b/src/backend/executor/execExprInterp.c @@ -446,6 +446,7 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull) &&CASE_EEOP_PARAM_EXEC, &&CASE_EEOP_PARAM_EXTERN, &&CASE_EEOP_PARAM_CALLBACK, + &&CASE_EEOP_PARAM_SET, &&CASE_EEOP_CASE_TESTVAL, &&CASE_EEOP_MAKE_READONLY, &&CASE_EEOP_IOCOERCE, @@ -1081,6 +1082,13 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull) EEO_NEXT(); } + EEO_CASE(EEOP_PARAM_SET) + { + /* out of line, unlikely to matter performancewise */ + ExecEvalParamSet(state, op, econtext); + EEO_NEXT(); + } + EEO_CASE(EEOP_CASE_TESTVAL) { /* @@ -2477,6 +2485,20 @@ ExecEvalParamExtern(ExprState *state, ExprEvalStep *op, ExprContext *econtext) errmsg("no value found for parameter %d", paramId))); } +/* + * Set value of a param (currently always PARAM_EXEC) from + * state->res{value,null}. + */ +void +ExecEvalParamSet(ExprState *state, ExprEvalStep *op, ExprContext *econtext) +{ + ParamExecData *prm; + + prm = &(econtext->ecxt_param_exec_vals[op->d.param.paramid]); + prm->value = state->resvalue; + prm->isnull = state->resnull; +} + /* * Raise error if a CURRENT OF expression is evaluated. * diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c index 4d288bc8d41..f62bb28140f 100644 --- a/src/backend/executor/execProcnode.c +++ b/src/backend/executor/execProcnode.c @@ -393,6 +393,10 @@ ExecInitNode(Plan *node, EState *estate, int eflags) /* * Initialize any initPlans present in this node. The planner put them in * a separate list for us. + * + * The defining characteristic of initplans is that they don't have + * arguments, so we don't need to evaluate them (in contrast to + * ExecInitSubPlanExpr()). */ subps = NIL; foreach(l, node->initPlan) @@ -401,6 +405,7 @@ ExecInitNode(Plan *node, EState *estate, int eflags) SubPlanState *sstate; Assert(IsA(subplan, SubPlan)); + Assert(subplan->args == NIL); sstate = ExecInitSubPlan(subplan, result); subps = lappend(subps, sstate); } diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index c136f75ac24..3458ac007cd 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -107,7 +107,7 @@ ExecHashSubPlan(SubPlanState *node, TupleTableSlot *slot; /* Shouldn't have any direct correlation Vars */ - if (subplan->parParam != NIL || node->args != NIL) + if (subplan->parParam != NIL || subplan->args != NIL) elog(ERROR, "hashed subplan with direct correlation not supported"); /* @@ -231,7 +231,6 @@ ExecScanSubPlan(SubPlanState *node, TupleTableSlot *slot; Datum result; bool found = false; /* true if got at least one subplan tuple */ - ListCell *pvar; ListCell *l; ArrayBuildStateAny *astate = NULL; @@ -248,26 +247,20 @@ ExecScanSubPlan(SubPlanState *node, oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory); /* - * Set Params of this plan from parent plan correlation values. (Any - * calculation we have to do is done in the parent econtext, since the - * Param values don't need to have per-query lifetime.) + * We rely on the caller to evaluate plan correlation values, if + * necessary. However we still need to record the fact that the values + * (might have) changed, otherwise the ExecReScan() below won't know that + * nodes need to be rescanned. */ - Assert(list_length(subplan->parParam) == list_length(node->args)); - - forboth(l, subplan->parParam, pvar, node->args) + Assert(list_length(subplan->parParam) == list_length(subplan->args)); + foreach(l, subplan->parParam) { int paramid = lfirst_int(l); - ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]); - prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar), - econtext, - &(prm->isnull)); planstate->chgParam = bms_add_member(planstate->chgParam, paramid); } - /* - * Now that we've set up its parameters, we can reset the subplan. - */ + /* with that done, we can reset the subplan */ ExecReScan(planstate); /* @@ -817,6 +810,10 @@ slotNoNulls(TupleTableSlot *slot) * as well as regular SubPlans. Note that we don't link the SubPlan into * the parent's subPlan list, because that shouldn't happen for InitPlans. * Instead, ExecInitExpr() does that one part. + * + * We also rely on ExecInitExpr(), more precisely ExecInitSubPlanExpr(), to + * evaluate input parameters, as that allows them to be evaluated as part of + * the expression referencing the SubPlan. * ---------------------------------------------------------------- */ SubPlanState * @@ -844,7 +841,6 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent) /* Initialize subexpressions */ sstate->testexpr = ExecInitExpr((Expr *) subplan->testexpr, parent); - sstate->args = ExecInitExprList(subplan->args, parent); /* * initialize my state @@ -1107,7 +1103,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext) elog(ERROR, "ANY/ALL subselect unsupported as initplan"); if (subLinkType == CTE_SUBLINK) elog(ERROR, "CTE subplans should not be executed via ExecSetParamPlan"); - if (subplan->parParam || node->args) + if (subplan->parParam || subplan->args) elog(ERROR, "correlated subplans should not be executed via ExecSetParamPlan"); /* diff --git a/src/backend/jit/llvm/llvmjit_expr.c b/src/backend/jit/llvm/llvmjit_expr.c index 1c722c79552..812f8758743 100644 --- a/src/backend/jit/llvm/llvmjit_expr.c +++ b/src/backend/jit/llvm/llvmjit_expr.c @@ -1094,6 +1094,12 @@ llvm_compile_expr(ExprState *state) break; } + case EEOP_PARAM_SET: + build_EvalXFunc(b, mod, "ExecEvalParamSet", + v_state, op, v_econtext); + LLVMBuildBr(b, opblocks[opno + 1]); + break; + case EEOP_SBSREF_SUBSCRIPTS: { int jumpdone = op->d.sbsref_subscript.jumpdone; diff --git a/src/backend/jit/llvm/llvmjit_types.c b/src/backend/jit/llvm/llvmjit_types.c index 876fb640294..0b1df3afe00 100644 --- a/src/backend/jit/llvm/llvmjit_types.c +++ b/src/backend/jit/llvm/llvmjit_types.c @@ -123,6 +123,7 @@ void *referenced_functions[] = ExecEvalNextValueExpr, ExecEvalParamExec, ExecEvalParamExtern, + ExecEvalParamSet, ExecEvalRow, ExecEvalRowNotNull, ExecEvalRowNull, -- 2.37.1.188.g71a8fab31b --2fo66m5ddj2bowyf-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState @ 2023-02-25 21:39 Andres Freund <andres@anarazel.de> 0 siblings, 0 replies; 653+ messages in thread From: Andres Freund @ 2023-02-25 21:39 UTC (permalink / raw) --- src/include/nodes/execnodes.h | 1 - src/backend/executor/execExpr.c | 81 +++++++++++++++++------------ src/backend/executor/execProcnode.c | 5 ++ src/backend/executor/nodeSubplan.c | 30 +++++------ 4 files changed, 66 insertions(+), 51 deletions(-) diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 20f4c8b35f3..437cf8b5a02 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -947,7 +947,6 @@ typedef struct SubPlanState struct PlanState *planstate; /* subselect plan's state tree */ struct PlanState *parent; /* parent plan node's state tree */ ExprState *testexpr; /* state of combining expression */ - List *args; /* states of argument expression(s) */ HeapTuple curTuple; /* copy of most recent tuple from subplan */ Datum curArray; /* most recent array from ARRAY() subplan */ /* these are used when hashing the subselect's output: */ diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c index c61f23c6c18..7a9d5729b4b 100644 --- a/src/backend/executor/execExpr.c +++ b/src/backend/executor/execExpr.c @@ -87,6 +87,9 @@ static void ExecBuildAggTransCall(ExprState *state, AggState *aggstate, FunctionCallInfo fcinfo, AggStatePerTrans pertrans, int transno, int setno, int setoff, bool ishash, bool nullcheck); +static void ExecInitSubPlanExpr(SubPlan *subplan, + ExprState *state, + Datum *resv, bool *resnull); /* @@ -1388,7 +1391,6 @@ ExecInitExprRec(Expr *node, ExprState *state, case T_SubPlan: { SubPlan *subplan = (SubPlan *) node; - SubPlanState *sstate; /* * Real execution of a MULTIEXPR SubPlan has already been @@ -1405,19 +1407,7 @@ ExecInitExprRec(Expr *node, ExprState *state, break; } - if (!state->parent) - elog(ERROR, "SubPlan found with no parent plan"); - - sstate = ExecInitSubPlan(subplan, state->parent); - - /* add SubPlanState nodes to state->parent->subPlan */ - state->parent->subPlan = lappend(state->parent->subPlan, - sstate); - - scratch.opcode = EEOP_SUBPLAN; - scratch.d.subplan.sstate = sstate; - - ExprEvalPushStep(state, &scratch); + ExecInitSubPlanExpr(subplan, state, resv, resnull); break; } @@ -2618,29 +2608,12 @@ ExecPushExprSetupSteps(ExprState *state, ExprSetupInfo *info) foreach(lc, info->multiexpr_subplans) { SubPlan *subplan = (SubPlan *) lfirst(lc); - SubPlanState *sstate; Assert(subplan->subLinkType == MULTIEXPR_SUBLINK); - /* This should match what ExecInitExprRec does for other SubPlans: */ - - if (!state->parent) - elog(ERROR, "SubPlan found with no parent plan"); - - sstate = ExecInitSubPlan(subplan, state->parent); - - /* add SubPlanState nodes to state->parent->subPlan */ - state->parent->subPlan = lappend(state->parent->subPlan, - sstate); - - scratch.opcode = EEOP_SUBPLAN; - scratch.d.subplan.sstate = sstate; - /* The result can be ignored, but we better put it somewhere */ - scratch.resvalue = &state->resvalue; - scratch.resnull = &state->resnull; - - ExprEvalPushStep(state, &scratch); + ExecInitSubPlanExpr(subplan, state, + &state->resvalue, &state->resnull); } } @@ -4040,3 +4013,45 @@ ExecBuildParamSetEqual(TupleDesc desc, return state; } + +static void +ExecInitSubPlanExpr(SubPlan *subplan, + ExprState *state, + Datum *resv, bool *resnull) +{ + ExprEvalStep scratch = {0}; + SubPlanState *sstate; + ListCell *pvar; + ListCell *l; + EState *estate = state->parent->state; + + if (!state->parent) + elog(ERROR, "SubPlan found with no parent plan"); + + /* + * Generate steps to evaluate input arguments for the subplan. + * + * Any calculation we have to do can be done in the parent econtext, since + * the Param values don't need to have per-query lifetime. + */ + forboth(l, subplan->parParam, pvar, subplan->args) + { + int paramid = lfirst_int(l); + ParamExecData *prm = &estate->es_param_exec_vals[paramid]; + + ExecInitExprRec(lfirst(pvar), state, &prm->value, &prm->isnull); + } + + sstate = ExecInitSubPlan(subplan, state->parent); + + /* add SubPlanState nodes to state->parent->subPlan */ + state->parent->subPlan = lappend(state->parent->subPlan, + sstate); + + scratch.opcode = EEOP_SUBPLAN; + scratch.resvalue = resv; + scratch.resnull = resnull; + scratch.d.subplan.sstate = sstate; + + ExprEvalPushStep(state, &scratch); +} diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c index 4d288bc8d41..f62bb28140f 100644 --- a/src/backend/executor/execProcnode.c +++ b/src/backend/executor/execProcnode.c @@ -393,6 +393,10 @@ ExecInitNode(Plan *node, EState *estate, int eflags) /* * Initialize any initPlans present in this node. The planner put them in * a separate list for us. + * + * The defining characteristic of initplans is that they don't have + * arguments, so we don't need to evaluate them (in contrast to + * ExecInitSubPlanExpr()). */ subps = NIL; foreach(l, node->initPlan) @@ -401,6 +405,7 @@ ExecInitNode(Plan *node, EState *estate, int eflags) SubPlanState *sstate; Assert(IsA(subplan, SubPlan)); + Assert(subplan->args == NIL); sstate = ExecInitSubPlan(subplan, result); subps = lappend(subps, sstate); } diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index c136f75ac24..3458ac007cd 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -107,7 +107,7 @@ ExecHashSubPlan(SubPlanState *node, TupleTableSlot *slot; /* Shouldn't have any direct correlation Vars */ - if (subplan->parParam != NIL || node->args != NIL) + if (subplan->parParam != NIL || subplan->args != NIL) elog(ERROR, "hashed subplan with direct correlation not supported"); /* @@ -231,7 +231,6 @@ ExecScanSubPlan(SubPlanState *node, TupleTableSlot *slot; Datum result; bool found = false; /* true if got at least one subplan tuple */ - ListCell *pvar; ListCell *l; ArrayBuildStateAny *astate = NULL; @@ -248,26 +247,20 @@ ExecScanSubPlan(SubPlanState *node, oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory); /* - * Set Params of this plan from parent plan correlation values. (Any - * calculation we have to do is done in the parent econtext, since the - * Param values don't need to have per-query lifetime.) + * We rely on the caller to evaluate plan correlation values, if + * necessary. However we still need to record the fact that the values + * (might have) changed, otherwise the ExecReScan() below won't know that + * nodes need to be rescanned. */ - Assert(list_length(subplan->parParam) == list_length(node->args)); - - forboth(l, subplan->parParam, pvar, node->args) + Assert(list_length(subplan->parParam) == list_length(subplan->args)); + foreach(l, subplan->parParam) { int paramid = lfirst_int(l); - ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]); - prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar), - econtext, - &(prm->isnull)); planstate->chgParam = bms_add_member(planstate->chgParam, paramid); } - /* - * Now that we've set up its parameters, we can reset the subplan. - */ + /* with that done, we can reset the subplan */ ExecReScan(planstate); /* @@ -817,6 +810,10 @@ slotNoNulls(TupleTableSlot *slot) * as well as regular SubPlans. Note that we don't link the SubPlan into * the parent's subPlan list, because that shouldn't happen for InitPlans. * Instead, ExecInitExpr() does that one part. + * + * We also rely on ExecInitExpr(), more precisely ExecInitSubPlanExpr(), to + * evaluate input parameters, as that allows them to be evaluated as part of + * the expression referencing the SubPlan. * ---------------------------------------------------------------- */ SubPlanState * @@ -844,7 +841,6 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent) /* Initialize subexpressions */ sstate->testexpr = ExecInitExpr((Expr *) subplan->testexpr, parent); - sstate->args = ExecInitExprList(subplan->args, parent); /* * initialize my state @@ -1107,7 +1103,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext) elog(ERROR, "ANY/ALL subselect unsupported as initplan"); if (subLinkType == CTE_SUBLINK) elog(ERROR, "CTE subplans should not be executed via ExecSetParamPlan"); - if (subplan->parParam || node->args) + if (subplan->parParam || subplan->args) elog(ERROR, "correlated subplans should not be executed via ExecSetParamPlan"); /* -- 2.38.0 --6ir4gcdcv6d4j3qy-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v15 5/8] Row pattern recognition patch (executor). @ 2024-03-28 10:30 Tatsuo Ishii <ishii@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw) --- src/backend/executor/nodeWindowAgg.c | 1617 +++++++++++++++++++++++++- src/backend/utils/adt/windowfuncs.c | 37 +- src/include/catalog/pg_proc.dat | 6 + src/include/nodes/execnodes.h | 30 + 4 files changed, 1679 insertions(+), 11 deletions(-) diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c index 3221fa1522..9606e7d463 100644 --- a/src/backend/executor/nodeWindowAgg.c +++ b/src/backend/executor/nodeWindowAgg.c @@ -36,6 +36,7 @@ #include "access/htup_details.h" #include "catalog/objectaccess.h" #include "catalog/pg_aggregate.h" +#include "catalog/pg_collation_d.h" #include "catalog/pg_proc.h" #include "executor/executor.h" #include "executor/nodeWindowAgg.h" @@ -48,6 +49,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/datum.h" +#include "utils/fmgroids.h" #include "utils/expandeddatum.h" #include "utils/lsyscache.h" #include "utils/memutils.h" @@ -159,6 +161,43 @@ typedef struct WindowStatePerAggData bool restart; /* need to restart this agg in this cycle? */ } WindowStatePerAggData; +/* + * Set of StringInfo. Used in RPR. + */ +typedef struct StringSet +{ + StringInfo *str_set; + Size set_size; /* current array allocation size in number of + * items */ + int set_index; /* current used size */ +} StringSet; + +/* + * Allowed subsequent PATTERN variables positions. + * Used in RPR. + * + * pos represents the pattern variable defined order in DEFINE caluase. For + * example. "DEFINE START..., UP..., DOWN ..." and "PATTERN START UP DOWN UP" + * will create: + * VariablePos[0].pos[0] = 0; START + * VariablePos[1].pos[0] = 1; UP + * VariablePos[1].pos[1] = 3; UP + * VariablePos[2].pos[0] = 2; DOWN + * + * Note that UP has two pos because UP appears in PATTERN twice. + * + * By using this strucrture, we can know which pattern variable can be followed + * by which pattern variable(s). For example, START can be followed by UP and + * DOWN since START's pos is 0, and UP's pos is 1 or 3, DOWN's pos is 2. + * DOWN can be followed by UP since UP's pos is either 1 or 3. + * + */ +#define NUM_ALPHABETS 26 /* we allow [a-z] variable initials */ +typedef struct VariablePos +{ + int pos[NUM_ALPHABETS]; /* postion(s) in PATTERN */ +} VariablePos; + static void initialize_windowaggregate(WindowAggState *winstate, WindowStatePerFunc perfuncstate, WindowStatePerAgg peraggstate); @@ -184,6 +223,7 @@ static void release_partition(WindowAggState *winstate); static int row_is_in_frame(WindowAggState *winstate, int64 pos, TupleTableSlot *slot); + static void update_frameheadpos(WindowAggState *winstate); static void update_frametailpos(WindowAggState *winstate); static void update_grouptailpos(WindowAggState *winstate); @@ -195,9 +235,48 @@ static Datum GetAggInitVal(Datum textInitVal, Oid transtype); static bool are_peers(WindowAggState *winstate, TupleTableSlot *slot1, TupleTableSlot *slot2); + +static int WinGetSlotInFrame(WindowObject winobj, TupleTableSlot *slot, + int relpos, int seektype, bool set_mark, + bool *isnull, bool *isout); static bool window_gettupleslot(WindowObject winobj, int64 pos, TupleTableSlot *slot); +static void attno_map(Node *node); +static bool attno_map_walker(Node *node, void *context); +static int row_is_in_reduced_frame(WindowObject winobj, int64 pos); +static bool rpr_is_defined(WindowAggState *winstate); + +static void create_reduced_frame_map(WindowAggState *winstate); +static int get_reduced_frame_map(WindowAggState *winstate, int64 pos); +static void register_reduced_frame_map(WindowAggState *winstate, int64 pos, + int val); +static void clear_reduced_frame_map(WindowAggState *winstate); +static void update_reduced_frame(WindowObject winobj, int64 pos); + +static int64 evaluate_pattern(WindowObject winobj, int64 current_pos, + char *vname, StringInfo encoded_str, bool *result); + +static bool get_slots(WindowObject winobj, int64 current_pos); + +static int search_str_set(char *pattern, StringSet * str_set, + VariablePos * variable_pos); +static char pattern_initial(WindowAggState *winstate, char *vname); +static int do_pattern_match(char *pattern, char *encoded_str); + +static StringSet * string_set_init(void); +static void string_set_add(StringSet * string_set, StringInfo str); +static StringInfo string_set_get(StringSet * string_set, int index); +static int string_set_get_size(StringSet * string_set); +static void string_set_discard(StringSet * string_set); +static VariablePos * variable_pos_init(void); +static void variable_pos_register(VariablePos * variable_pos, char initial, + int pos); +static bool variable_pos_compare(VariablePos * variable_pos, + char initial1, char initial2); +static int variable_pos_fetch(VariablePos * variable_pos, char initial, + int index); +static void variable_pos_discard(VariablePos * variable_pos); /* * initialize_windowaggregate @@ -673,6 +752,7 @@ eval_windowaggregates(WindowAggState *winstate) WindowObject agg_winobj; TupleTableSlot *agg_row_slot; TupleTableSlot *temp_slot; + bool agg_result_isnull; numaggs = winstate->numaggs; if (numaggs == 0) @@ -778,6 +858,9 @@ eval_windowaggregates(WindowAggState *winstate) * Note that we don't strictly need to restart in the last case, but if * we're going to remove all rows from the aggregation anyway, a restart * surely is faster. + * + * - if RPR is enabled and skip mode is SKIP TO NEXT ROW, + * we restart aggregation too. *---------- */ numaggs_restart = 0; @@ -788,8 +871,11 @@ eval_windowaggregates(WindowAggState *winstate) (winstate->aggregatedbase != winstate->frameheadpos && !OidIsValid(peraggstate->invtransfn_oid)) || (winstate->frameOptions & FRAMEOPTION_EXCLUSION) || - winstate->aggregatedupto <= winstate->frameheadpos) + winstate->aggregatedupto <= winstate->frameheadpos || + (rpr_is_defined(winstate) && + winstate->rpSkipTo == ST_NEXT_ROW)) { + elog(DEBUG1, "peraggstate->restart is set"); peraggstate->restart = true; numaggs_restart++; } @@ -862,7 +948,22 @@ eval_windowaggregates(WindowAggState *winstate) * head, so that tuplestore can discard unnecessary rows. */ if (agg_winobj->markptr >= 0) - WinSetMarkPosition(agg_winobj, winstate->frameheadpos); + { + int64 markpos = winstate->frameheadpos; + + if (rpr_is_defined(winstate)) + { + /* + * If RPR is used, it is possible PREV wants to look at the + * previous row. So the mark pos should be frameheadpos - 1 + * unless it is below 0. + */ + markpos -= 1; + if (markpos < 0) + markpos = 0; + } + WinSetMarkPosition(agg_winobj, markpos); + } /* * Now restart the aggregates that require it. @@ -917,6 +1018,30 @@ eval_windowaggregates(WindowAggState *winstate) { winstate->aggregatedupto = winstate->frameheadpos; ExecClearTuple(agg_row_slot); + + /* + * If RPR is defined, we do not use aggregatedupto_nonrestarted. To + * avoid assertion failure below, we reset aggregatedupto_nonrestarted + * to frameheadpos. + */ + if (rpr_is_defined(winstate)) + aggregatedupto_nonrestarted = winstate->frameheadpos; + } + + agg_result_isnull = false; + /* RPR is defined? */ + if (rpr_is_defined(winstate)) + { + /* + * If the skip mode is SKIP TO PAST LAST ROW and we already know that + * current row is a skipped row, we don't need to accumulate rows, + * just return NULL. Note that for unamtched row, we need to do + * aggregation so that count(*) shows 0, rather than NULL. + */ + if (winstate->rpSkipTo == ST_PAST_LAST_ROW && + get_reduced_frame_map(winstate, + winstate->currentpos) == RF_SKIPPED) + agg_result_isnull = true; } /* @@ -930,6 +1055,12 @@ eval_windowaggregates(WindowAggState *winstate) { int ret; + elog(DEBUG1, "===== loop in frame starts: " INT64_FORMAT, + winstate->aggregatedupto); + + if (agg_result_isnull) + break; + /* Fetch next row if we didn't already */ if (TupIsNull(agg_row_slot)) { @@ -945,9 +1076,32 @@ eval_windowaggregates(WindowAggState *winstate) ret = row_is_in_frame(winstate, winstate->aggregatedupto, agg_row_slot); if (ret < 0) break; + if (ret == 0) goto next_tuple; + if (rpr_is_defined(winstate)) + { + /* + * If the row status at currentpos is already decided and current + * row status is not decided yet, it means we passed the last + * reduced frame. Time to break the loop. + */ + if (get_reduced_frame_map(winstate, + winstate->currentpos) != RF_NOT_DETERMINED && + get_reduced_frame_map(winstate, + winstate->aggregatedupto) == RF_NOT_DETERMINED) + break; + + /* + * Otherwise we need to calculate the reduced frame. + */ + ret = row_is_in_reduced_frame(winstate->agg_winobj, + winstate->aggregatedupto); + if (ret == -1) /* unmatched row */ + break; + } + /* Set tuple context for evaluation of aggregate arguments */ winstate->tmpcontext->ecxt_outertuple = agg_row_slot; @@ -976,6 +1130,7 @@ next_tuple: ExecClearTuple(agg_row_slot); } + /* The frame's end is not supposed to move backwards, ever */ Assert(aggregatedupto_nonrestarted <= winstate->aggregatedupto); @@ -996,6 +1151,16 @@ next_tuple: peraggstate, result, isnull); + /* + * RPR is defined and we just return NULL because skip mode is SKIP TO + * PAST LAST ROW and current row is skipped row. + */ + if (agg_result_isnull) + { + *isnull = true; + *result = (Datum) 0; + } + /* * save the result in case next row shares the same frame. * @@ -1090,6 +1255,7 @@ begin_partition(WindowAggState *winstate) winstate->framehead_valid = false; winstate->frametail_valid = false; winstate->grouptail_valid = false; + create_reduced_frame_map(winstate); winstate->spooled_rows = 0; winstate->currentpos = 0; winstate->frameheadpos = 0; @@ -2053,6 +2219,11 @@ ExecWindowAgg(PlanState *pstate) CHECK_FOR_INTERRUPTS(); +#ifdef RPR_DEBUG + elog(DEBUG1, "ExecWindowAgg called. pos: " INT64_FORMAT, + winstate->currentpos); +#endif + if (winstate->status == WINDOWAGG_DONE) return NULL; @@ -2221,6 +2392,17 @@ ExecWindowAgg(PlanState *pstate) /* don't evaluate the window functions when we're in pass-through mode */ if (winstate->status == WINDOWAGG_RUN) { + /* + * If RPR is defined and skip mode is next row, we need to clear + * existing reduced frame info so that we newly calculate the info + * starting from current row. + */ + if (rpr_is_defined(winstate)) + { + if (winstate->rpSkipTo == ST_NEXT_ROW) + clear_reduced_frame_map(winstate); + } + /* * Evaluate true window functions */ @@ -2388,6 +2570,9 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) TupleDesc scanDesc; ListCell *l; + TargetEntry *te; + Expr *expr; + /* check for unsupported flags */ Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK))); @@ -2486,6 +2671,16 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) winstate->temp_slot_2 = ExecInitExtraTupleSlot(estate, scanDesc, &TTSOpsMinimalTuple); + winstate->prev_slot = ExecInitExtraTupleSlot(estate, scanDesc, + &TTSOpsMinimalTuple); + + winstate->next_slot = ExecInitExtraTupleSlot(estate, scanDesc, + &TTSOpsMinimalTuple); + + winstate->null_slot = ExecInitExtraTupleSlot(estate, scanDesc, + &TTSOpsMinimalTuple); + winstate->null_slot = ExecStoreAllNullTuple(winstate->null_slot); + /* * create frame head and tail slots only if needed (must create slots in * exactly the same cases that update_frameheadpos and update_frametailpos @@ -2667,6 +2862,43 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) winstate->inRangeAsc = node->inRangeAsc; winstate->inRangeNullsFirst = node->inRangeNullsFirst; + /* Set up SKIP TO type */ + winstate->rpSkipTo = node->rpSkipTo; + /* Set up row pattern recognition PATTERN clause */ + winstate->patternVariableList = node->patternVariable; + winstate->patternRegexpList = node->patternRegexp; + + /* Set up row pattern recognition DEFINE clause */ + winstate->defineInitial = node->defineInitial; + winstate->defineVariableList = NIL; + winstate->defineClauseList = NIL; + if (node->defineClause != NIL) + { + /* + * Tweak arg var of PREV/NEXT so that it refers to scan/inner slot. + */ + foreach(l, node->defineClause) + { + char *name; + ExprState *exps; + + te = lfirst(l); + name = te->resname; + expr = te->expr; + +#ifdef RPR_DEBUG + elog(DEBUG1, "defineVariable name: %s", name); +#endif + winstate->defineVariableList = + lappend(winstate->defineVariableList, + makeString(pstrdup(name))); + attno_map((Node *) expr); + exps = ExecInitExpr(expr, (PlanState *) winstate); + winstate->defineClauseList = + lappend(winstate->defineClauseList, exps); + } + } + winstate->all_first = true; winstate->partition_spooled = false; winstate->more_partitions = false; @@ -2674,6 +2906,64 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags) return winstate; } +/* + * Rewrite varno of Var node that is the argument of PREV/NET so that it sees + * scan tuple (PREV) or inner tuple (NEXT). + */ +static void +attno_map(Node *node) +{ + (void) expression_tree_walker(node, attno_map_walker, NULL); +} + +static bool +attno_map_walker(Node *node, void *context) +{ + FuncExpr *func; + int nargs; + Expr *expr; + Var *var; + + if (node == NULL) + return false; + + if (IsA(node, FuncExpr)) + { + func = (FuncExpr *) node; + + if (func->funcid == F_PREV || func->funcid == F_NEXT) + { + /* sanity check */ + nargs = list_length(func->args); + if (list_length(func->args) != 1) + elog(ERROR, "PREV/NEXT must have 1 argument but function %d has %d args", + func->funcid, nargs); + + expr = (Expr *) lfirst(list_head(func->args)); + if (!IsA(expr, Var)) + elog(ERROR, "PREV/NEXT's arg is not Var"); /* XXX: is it possible + * that arg type is + * Const? */ + var = (Var *) expr; + + if (func->funcid == F_PREV) + + /* + * Rewrite varno from OUTER_VAR to regular var no so that the + * var references scan tuple. + */ + var->varno = var->varnosyn; + else + var->varno = INNER_VAR; + +#ifdef RPR_DEBUG + elog(DEBUG1, "PREV/NEXT's varno is rewritten to: %d", var->varno); +#endif + } + } + return expression_tree_walker(node, attno_map_walker, NULL); +} + /* ----------------- * ExecEndWindowAgg * ----------------- @@ -2723,6 +3013,8 @@ ExecReScanWindowAgg(WindowAggState *node) ExecClearTuple(node->agg_row_slot); ExecClearTuple(node->temp_slot_1); ExecClearTuple(node->temp_slot_2); + ExecClearTuple(node->prev_slot); + ExecClearTuple(node->next_slot); if (node->framehead_slot) ExecClearTuple(node->framehead_slot); if (node->frametail_slot) @@ -3083,7 +3375,8 @@ window_gettupleslot(WindowObject winobj, int64 pos, TupleTableSlot *slot) return false; if (pos < winobj->markpos) - elog(ERROR, "cannot fetch row before WindowObject's mark position"); + elog(ERROR, "cannot fetch row: " INT64_FORMAT " before WindowObject's mark position: " INT64_FORMAT, + pos, winobj->markpos); oldcontext = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_query_memory); @@ -3403,14 +3696,54 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno, WindowAggState *winstate; ExprContext *econtext; TupleTableSlot *slot; - int64 abs_pos; - int64 mark_pos; Assert(WindowObjectIsValid(winobj)); winstate = winobj->winstate; econtext = winstate->ss.ps.ps_ExprContext; slot = winstate->temp_slot_1; + if (WinGetSlotInFrame(winobj, slot, + relpos, seektype, set_mark, + isnull, isout) == 0) + { + econtext->ecxt_outertuple = slot; + return ExecEvalExpr((ExprState *) list_nth(winobj->argstates, argno), + econtext, isnull); + } + + if (isout) + *isout = true; + *isnull = true; + return (Datum) 0; +} + +/* + * WinGetSlotInFrame + * slot: TupleTableSlot to store the result + * relpos: signed rowcount offset from the seek position + * seektype: WINDOW_SEEK_HEAD or WINDOW_SEEK_TAIL + * set_mark: If the row is found/in frame and set_mark is true, the mark is + * moved to the row as a side-effect. + * isnull: output argument, receives isnull status of result + * isout: output argument, set to indicate whether target row position + * is out of frame (can pass NULL if caller doesn't care about this) + * + * Returns 0 if we successfullt got the slot. false if out of frame. + * (also isout is set) + */ +static int +WinGetSlotInFrame(WindowObject winobj, TupleTableSlot *slot, + int relpos, int seektype, bool set_mark, + bool *isnull, bool *isout) +{ + WindowAggState *winstate; + int64 abs_pos; + int64 mark_pos; + int num_reduced_frame; + + Assert(WindowObjectIsValid(winobj)); + winstate = winobj->winstate; + switch (seektype) { case WINDOW_SEEK_CURRENT: @@ -3477,11 +3810,25 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno, winstate->frameOptions); break; } + num_reduced_frame = row_is_in_reduced_frame(winobj, + winstate->frameheadpos); + if (num_reduced_frame < 0) + goto out_of_frame; + else if (num_reduced_frame > 0) + if (relpos >= num_reduced_frame) + goto out_of_frame; break; case WINDOW_SEEK_TAIL: /* rejecting relpos > 0 is easy and simplifies code below */ if (relpos > 0) goto out_of_frame; + + /* + * RPR cares about frame head pos. Need to call + * update_frameheadpos + */ + update_frameheadpos(winstate); + update_frametailpos(winstate); abs_pos = winstate->frametailpos - 1 + relpos; @@ -3548,6 +3895,14 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno, mark_pos = 0; /* keep compiler quiet */ break; } + + num_reduced_frame = row_is_in_reduced_frame(winobj, + winstate->frameheadpos + relpos); + if (num_reduced_frame < 0) + goto out_of_frame; + else if (num_reduced_frame > 0) + abs_pos = winstate->frameheadpos + relpos + + num_reduced_frame - 1; break; default: elog(ERROR, "unrecognized window seek type: %d", seektype); @@ -3566,15 +3921,13 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno, *isout = false; if (set_mark) WinSetMarkPosition(winobj, mark_pos); - econtext->ecxt_outertuple = slot; - return ExecEvalExpr((ExprState *) list_nth(winobj->argstates, argno), - econtext, isnull); + return 0; out_of_frame: if (isout) *isout = true; *isnull = true; - return (Datum) 0; + return -1; } /* @@ -3605,3 +3958,1249 @@ WinGetFuncArgCurrent(WindowObject winobj, int argno, bool *isnull) return ExecEvalExpr((ExprState *) list_nth(winobj->argstates, argno), econtext, isnull); } + +/* + * rpr_is_defined + * return true if Row pattern recognition is defined. + */ +static +bool +rpr_is_defined(WindowAggState *winstate) +{ + return winstate->patternVariableList != NIL; +} + +/* + * row_is_in_reduced_frame + * Determine whether a row is in the current row's reduced window frame + * according to row pattern matching + * + * The row must has been already determined that it is in a full window frame + * and fetched it into slot. + * + * Returns: + * = 0, RPR is not defined. + * >0, if the row is the first in the reduced frame. Return the number of rows + * in the reduced frame. + * -1, if the row is unmatched row + * -2, if the row is in the reduced frame but needed to be skipped because of + * AFTER MATCH SKIP PAST LAST ROW + */ +static +int +row_is_in_reduced_frame(WindowObject winobj, int64 pos) +{ + WindowAggState *winstate = winobj->winstate; + int state; + int rtn; + + if (!rpr_is_defined(winstate)) + { + /* + * RPR is not defined. Assume that we are always in the the reduced + * window frame. + */ + rtn = 0; +#ifdef RPR_DEBUG + elog(DEBUG1, "row_is_in_reduced_frame returns %d: pos: " INT64_FORMAT, + rtn, pos); +#endif + return rtn; + } + + state = get_reduced_frame_map(winstate, pos); + + if (state == RF_NOT_DETERMINED) + { + update_frameheadpos(winstate); + update_reduced_frame(winobj, pos); + } + + state = get_reduced_frame_map(winstate, pos); + + switch (state) + { + int64 i; + int num_reduced_rows; + + case RF_FRAME_HEAD: + num_reduced_rows = 1; + for (i = pos + 1; + get_reduced_frame_map(winstate, i) == RF_SKIPPED; i++) + num_reduced_rows++; + rtn = num_reduced_rows; + break; + + case RF_SKIPPED: + rtn = -2; + break; + + case RF_UNMATCHED: + rtn = -1; + break; + + default: + elog(ERROR, "Unrecognized state: %d at: " INT64_FORMAT, + state, pos); + break; + } + +#ifdef RPR_DEBUG + elog(DEBUG1, "row_is_in_reduced_frame returns %d: pos: " INT64_FORMAT, + rtn, pos); +#endif + return rtn; +} + +#define REDUCED_FRAME_MAP_INIT_SIZE 1024L + +/* + * create_reduced_frame_map + * Create reduced frame map + */ +static +void +create_reduced_frame_map(WindowAggState *winstate) +{ + winstate->reduced_frame_map = + MemoryContextAlloc(winstate->partcontext, + REDUCED_FRAME_MAP_INIT_SIZE); + winstate->alloc_sz = REDUCED_FRAME_MAP_INIT_SIZE; + clear_reduced_frame_map(winstate); +} + +/* + * clear_reduced_frame_map + * Clear reduced frame map + */ +static +void +clear_reduced_frame_map(WindowAggState *winstate) +{ + Assert(winstate->reduced_frame_map != NULL); + MemSet(winstate->reduced_frame_map, RF_NOT_DETERMINED, + winstate->alloc_sz); +} + +/* + * get_reduced_frame_map + * Get reduced frame map specified by pos + */ +static +int +get_reduced_frame_map(WindowAggState *winstate, int64 pos) +{ + Assert(winstate->reduced_frame_map != NULL); + + if (pos < 0 || pos >= winstate->alloc_sz) + elog(ERROR, "wrong pos: " INT64_FORMAT, pos); + + return winstate->reduced_frame_map[pos]; +} + +/* + * register_reduced_frame_map + * Add/replace reduced frame map member at pos. + * If there's no enough space, expand the map. + */ +static +void +register_reduced_frame_map(WindowAggState *winstate, int64 pos, int val) +{ + int64 realloc_sz; + + Assert(winstate->reduced_frame_map != NULL); + + if (pos < 0) + elog(ERROR, "wrong pos: " INT64_FORMAT, pos); + + if (pos > winstate->alloc_sz - 1) + { + realloc_sz = winstate->alloc_sz * 2; + + winstate->reduced_frame_map = + repalloc(winstate->reduced_frame_map, realloc_sz); + + MemSet(winstate->reduced_frame_map + winstate->alloc_sz, + RF_NOT_DETERMINED, realloc_sz - winstate->alloc_sz); + + winstate->alloc_sz = realloc_sz; + } + + winstate->reduced_frame_map[pos] = val; +} + +/* + * update_reduced_frame + * Update reduced frame info. + */ +static +void +update_reduced_frame(WindowObject winobj, int64 pos) +{ + WindowAggState *winstate = winobj->winstate; + ListCell *lc1, + *lc2; + bool expression_result; + int num_matched_rows; + int64 original_pos; + bool anymatch; + StringInfo encoded_str; + StringInfo pattern_str = makeStringInfo(); + StringSet *str_set; + int initial_index; + VariablePos *variable_pos; + bool greedy = false; + int64 result_pos, + i; + + /* + * Set of pattern variables evaluated to true. Each character corresponds + * to pattern variable. Example: str_set[0] = "AB"; str_set[1] = "AC"; In + * this case at row 0 A and B are true, and A and C are true in row 1. + */ + + /* initialize pattern variables set */ + str_set = string_set_init(); + + /* save original pos */ + original_pos = pos; + + /* + * Check if the pattern does not include any greedy quantifier. If it does + * not, we can just apply the pattern to each row. If it succeeds, we are + * done. + */ + foreach(lc1, winstate->patternRegexpList) + { + char *quantifier = strVal(lfirst(lc1)); + + if (*quantifier == '+' || *quantifier == '*') + { + greedy = true; + break; + } + } + + /* + * Non greedy case + */ + if (!greedy) + { + num_matched_rows = 0; + + foreach(lc1, winstate->patternVariableList) + { + char *vname = strVal(lfirst(lc1)); + + encoded_str = makeStringInfo(); + +#ifdef RPR_DEBUG + elog(DEBUG1, "pos: " INT64_FORMAT " pattern vname: %s", + pos, vname); +#endif + expression_result = false; + + /* evaluate row pattern against current row */ + result_pos = evaluate_pattern(winobj, pos, vname, + encoded_str, &expression_result); + if (!expression_result || result_pos < 0) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "expression result is false or out of frame"); +#endif + register_reduced_frame_map(winstate, original_pos, + RF_UNMATCHED); + return; + } + /* move to next row */ + pos++; + num_matched_rows++; + } +#ifdef RPR_DEBUG + elog(DEBUG1, "pattern matched"); +#endif + register_reduced_frame_map(winstate, original_pos, RF_FRAME_HEAD); + + for (i = original_pos + 1; i < original_pos + num_matched_rows; i++) + { + register_reduced_frame_map(winstate, i, RF_SKIPPED); + } + return; + } + + /* + * Greedy quantifiers included. Loop over until none of pattern matches or + * encounters end of frame. + */ + for (;;) + { + result_pos = -1; + + /* + * Loop over each PATTERN variable. + */ + anymatch = false; + encoded_str = makeStringInfo(); + + forboth(lc1, winstate->patternVariableList, lc2, + winstate->patternRegexpList) + { + char *vname = strVal(lfirst(lc1)); +#ifdef RPR_DEBUG + char *quantifier = strVal(lfirst(lc2)); + + elog(DEBUG1, "pos: " INT64_FORMAT " pattern vname: %s quantifier: %s", + pos, vname, quantifier); +#endif + expression_result = false; + + /* evaluate row pattern against current row */ + result_pos = evaluate_pattern(winobj, pos, vname, + encoded_str, &expression_result); + if (expression_result) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "expression result is true"); +#endif + anymatch = true; + } + + /* + * If out of frame, we are done. + */ + if (result_pos < 0) + break; + } + + if (!anymatch) + { + /* none of patterns matched. */ + break; + } + + string_set_add(str_set, encoded_str); + +#ifdef RPR_DEBUG + elog(DEBUG1, "pos: " INT64_FORMAT " encoded_str: %s", + encoded_str->data); +#endif + + /* move to next row */ + pos++; + + if (result_pos < 0) + { + /* out of frame */ + break; + } + } + + if (string_set_get_size(str_set) == 0) + { + /* no match found in the first row */ + register_reduced_frame_map(winstate, original_pos, RF_UNMATCHED); + return; + } + +#ifdef RPR_DEBUG + elog(DEBUG2, "pos: " INT64_FORMAT " encoded_str: %s", + pos, encoded_str->data); +#endif + + /* build regular expression */ + pattern_str = makeStringInfo(); + appendStringInfoChar(pattern_str, '^'); + initial_index = 0; + + variable_pos = variable_pos_init(); + + forboth(lc1, winstate->patternVariableList, + lc2, winstate->patternRegexpList) + { + char *vname = strVal(lfirst(lc1)); + char *quantifier = strVal(lfirst(lc2)); + char initial; + + initial = pattern_initial(winstate, vname); + Assert(initial != 0); + appendStringInfoChar(pattern_str, initial); + if (quantifier[0]) + appendStringInfoChar(pattern_str, quantifier[0]); + + /* + * Register the initial at initial_index. If the initial appears more + * than once, all of it's initial_index will be recorded. This could + * happen if a pattern variable appears in the PATTERN clause more + * than once like "UP DOWN UP" "UP UP UP". + */ + variable_pos_register(variable_pos, initial, initial_index); + + initial_index++; + } + +#ifdef RPR_DEBUG + elog(DEBUG2, "pos: " INT64_FORMAT " pattern: %s", + pos, pattern_str->data); +#endif + + /* look for matching pattern variable sequence */ +#ifdef RPR_DEBUG + elog(DEBUG1, "search_str_set started"); +#endif + num_matched_rows = search_str_set(pattern_str->data, + str_set, variable_pos); +#ifdef RPR_DEBUG + elog(DEBUG1, "search_str_set returns: %d", num_matched_rows); +#endif + variable_pos_discard(variable_pos); + string_set_discard(str_set); + + /* + * We are at the first row in the reduced frame. Save the number of + * matched rows as the number of rows in the reduced frame. + */ + if (num_matched_rows <= 0) + { + /* no match */ + register_reduced_frame_map(winstate, original_pos, RF_UNMATCHED); + } + else + { + register_reduced_frame_map(winstate, original_pos, RF_FRAME_HEAD); + + for (i = original_pos + 1; i < original_pos + num_matched_rows; i++) + { + register_reduced_frame_map(winstate, i, RF_SKIPPED); + } + } + + return; +} + +/* + * search_str_set + * Perform pattern matching using "pattern" against str_set. pattern is a + * regular expression derived from PATTERN clause. Note that the regular + * expression string is prefixed by '^' and followed by initials represented + * in a same way as str_set. str_set is a set of StringInfo. Each StringInfo + * has a string comprising initials of pattern variable strings being true in + * a row. The initials are one of [a-y], parallel to the order of variable + * names in DEFINE clause. Suppose DEFINE has variables START, UP and DOWN. If + * PATTERN has START, UP+ and DOWN, then the initials in PATTERN will be 'a', + * 'b' and 'c'. The "pattern" will be "^ab+c". + * + * variable_pos is an array representing the order of pattern variable string + * initials in PATTERN clause. For example initial 'a' potion is in + * variable_pos[0].pos[0] = 0. Note that if the pattern is "START UP DOWN UP" + * (UP appears twice), then "UP" (initial is 'b') has two position 1 and + * 3. Thus variable_pos for b is variable_pos[1].pos[0] = 1 and + * variable_pos[1].pos[1] = 3. + * + * Returns the longest number of the matching rows (greedy matching) if + * quatifier '+' or '*' is included in "pattern". + */ +static +int +search_str_set(char *pattern, StringSet * str_set, VariablePos * variable_pos) +{ +#define MAX_CANDIDATE_NUM 10000 /* max pattern match candidate size */ +#define FREEZED_CHAR 'Z' /* a pattern is freezed if it ends with the + * char */ +#define DISCARD_CHAR 'z' /* a pattern is not need to keep */ + + int set_size; /* number of rows in the set */ + int resultlen; + int index; + StringSet *old_str_set, + *new_str_set; + int new_str_size; + int len; + + set_size = string_set_get_size(str_set); + new_str_set = string_set_init(); + len = 0; + resultlen = 0; + + /* + * Generate all possible pattern variable name initials as a set of + * StringInfo named "new_str_set". For example, if we have two rows + * having "ab" (row 0) and "ac" (row 1) in the input str_set, new_str_set + * will have set of StringInfo "aa", "ac", "ba" and "bc" in the end. + */ +#ifdef RPR_DEBUG + elog(DEBUG1, "pattern: %s set_size: %d", pattern, set_size); +#endif + for (index = 0; index < set_size; index++) + { + StringInfo str; /* search target row */ + char *p; + int old_set_size; + int i; + +#ifdef RPR_DEBUG + elog(DEBUG1, "index: %d", index); +#endif + if (index == 0) + { + /* copy variables in row 0 */ + str = string_set_get(str_set, index); + p = str->data; + + /* + * Loop over each new pattern variable char. + */ + while (*p) + { + StringInfo new = makeStringInfo(); + + /* add pattern variable char */ + appendStringInfoChar(new, *p); + /* add new one to string set */ + string_set_add(new_str_set, new); +#ifdef RPR_DEBUG + elog(DEBUG1, "old_str: NULL new_str: %s", new->data); +#endif + p++; /* next pattern variable */ + } + } + else /* index != 0 */ + { + old_str_set = new_str_set; + new_str_set = string_set_init(); + str = string_set_get(str_set, index); + old_set_size = string_set_get_size(old_str_set); + + /* + * Loop over each rows in the previous result set. + */ + for (i = 0; i < old_set_size; i++) + { + StringInfo new; + char last_old_char; + int old_str_len; + StringInfo old = string_set_get(old_str_set, i); + + p = old->data; + old_str_len = strlen(p); + if (old_str_len > 0) + last_old_char = p[old_str_len - 1]; + else + last_old_char = '\0'; + + /* Is this old set freezed? */ + if (last_old_char == FREEZED_CHAR) + { + /* if shorter match. we can discard it */ + if ((old_str_len - 1) < resultlen) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "discard this old set because shorter match: %s", + old->data); +#endif + continue; + } + +#ifdef RPR_DEBUG + elog(DEBUG1, "keep this old set: %s", old->data); +#endif + + /* move the old set to new_str_set */ + string_set_add(new_str_set, old); + old_str_set->str_set[i] = NULL; + continue; + } + /* Can this old set be discarded? */ + else if (last_old_char == DISCARD_CHAR) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "discard this old set: %s", old->data); +#endif + continue; + } + +#ifdef RPR_DEBUG + elog(DEBUG1, "str->data: %s", str->data); +#endif + + /* + * loop over each pattern variable initial char in the input + * set. + */ + for (p = str->data; *p; p++) + { + /* + * Optimization. Check if the row's pattern variable + * initial character position is greater than or equal to + * the old set's last pattern variable initial character + * position. For example, if the old set's last pattern + * variable initials are "ab", then the new pattern + * variable initial can be "b" or "c" but can not be "a", + * if the initials in PATTERN is something like "a b c" or + * "a b+ c+" etc. This optimization is possible when we + * only allow "+" quantifier. + */ + if (variable_pos_compare(variable_pos, last_old_char, *p)) + { + /* copy source string */ + new = makeStringInfo(); + enlargeStringInfo(new, old->len + 1); + appendStringInfoString(new, old->data); + /* add pattern variable char */ + appendStringInfoChar(new, *p); +#ifdef RPR_DEBUG + elog(DEBUG1, "old_str: %s new_str: %s", + old->data, new->data); +#endif + + /* + * Adhoc optimization. If the first letter in the + * input string is the first and second position one + * and there's no associated quatifier '+', then we + * can dicard the input because there's no chace to + * expand the string further. + * + * For example, pattern "abc" cannot match "aa". + */ +#ifdef RPR_DEBUG + elog(DEBUG1, "pattern[1]:%c pattern[2]:%c new[0]:%c new[1]:%c", + pattern[1], pattern[2], new->data[0], new->data[1]); +#endif + if (pattern[1] == new->data[0] && + pattern[1] == new->data[1] && + pattern[2] != '+' && + pattern[1] != pattern[2]) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "discard this new data: %s", + new->data); +#endif + pfree(new->data); + pfree(new); + continue; + } + + /* add new one to string set */ + string_set_add(new_str_set, new); + } + else + { + /* + * We are freezing this pattern string. Since there's + * no chance to expand the string further, we perform + * pattern matching against the string. If it does not + * match, we can discard it. + */ + len = do_pattern_match(pattern, old->data); + + if (len <= 0) + { + /* no match. we can discard it */ + continue; + } + + else if (len <= resultlen) + { + /* shorter match. we can discard it */ + continue; + } + else + { + /* match length is the longest so far */ + + int new_index; + + /* remember the longest match */ + resultlen = len; + + /* freeze the pattern string */ + new = makeStringInfo(); + enlargeStringInfo(new, old->len + 1); + appendStringInfoString(new, old->data); + /* add freezed mark */ + appendStringInfoChar(new, FREEZED_CHAR); +#ifdef RPR_DEBUG + elog(DEBUG1, "old_str: %s new_str: %s", old->data, new->data); +#endif + string_set_add(new_str_set, new); + + /* + * Search new_str_set to find out freezed entries + * that have shorter match length. Mark them as + * "discard" so that they are discarded in the + * next round. + */ + + /* new_index_size should be the one before */ + new_str_size = + string_set_get_size(new_str_set) - 1; + + /* loop over new_str_set */ + for (new_index = 0; new_index < new_str_size; + new_index++) + { + char new_last_char; + int new_str_len; + + new = string_set_get(new_str_set, new_index); + new_str_len = strlen(new->data); + if (new_str_len > 0) + { + new_last_char = + new->data[new_str_len - 1]; + if (new_last_char == FREEZED_CHAR && + (new_str_len - 1) <= len) + { + /* + * mark this set to discard in the + * next round + */ + appendStringInfoChar(new, DISCARD_CHAR); +#ifdef RPR_DEBUG + elog(DEBUG1, "add discard char: %s", new->data); +#endif + } + } + } + } + } + } + } + /* we no longer need old string set */ + string_set_discard(old_str_set); + } + } + + /* + * Perform pattern matching to find out the longest match. + */ + new_str_size = string_set_get_size(new_str_set); +#ifdef RPR_DEBUG + elog(DEBUG1, "new_str_size: %d", new_str_size); +#endif + len = 0; + resultlen = 0; + + for (index = 0; index < new_str_size; index++) + { + StringInfo s; + + s = string_set_get(new_str_set, index); + if (s == NULL) + continue; /* no data */ + +#ifdef RPR_DEBUG + elog(DEBUG1, "target string: %s", s->data); +#endif + len = do_pattern_match(pattern, s->data); + if (len > resultlen) + { + /* remember the longest match */ + resultlen = len; + + /* + * If the size of result set is equal to the number of rows in the + * set, we are done because it's not possible that the number of + * matching rows exceeds the number of rows in the set. + */ + if (resultlen >= set_size) + break; + } + } + + /* we no longer need new string set */ + string_set_discard(new_str_set); + + return resultlen; +} + +/* + * do_pattern_match + * perform pattern match using pattern against encoded_str. + * returns matching number of rows if matching is succeeded. + * Otherwise returns 0. + */ +static +int +do_pattern_match(char *pattern, char *encoded_str) +{ + Datum d; + text *res; + char *substr; + int len = 0; + text *pattern_text, + *encoded_str_text; + + pattern_text = cstring_to_text(pattern); + encoded_str_text = cstring_to_text(encoded_str); + + /* + * We first perform pattern matching using regexp_instr, then call + * textregexsubstr to get matched substring to know how long the matched + * string is. That is the number of rows in the reduced window frame. The + * reason why we can't call textregexsubstr in the first place is, it + * errors out if pattern does not match. + */ + if (DatumGetInt32(DirectFunctionCall2Coll( + regexp_instr, DEFAULT_COLLATION_OID, + PointerGetDatum(encoded_str_text), + PointerGetDatum(pattern_text)))) + { + d = DirectFunctionCall2Coll(textregexsubstr, + DEFAULT_COLLATION_OID, + PointerGetDatum(encoded_str_text), + PointerGetDatum(pattern_text)); + if (d != 0) + { + res = DatumGetTextPP(d); + substr = text_to_cstring(res); + len = strlen(substr); + pfree(substr); + } + } + pfree(encoded_str_text); + pfree(pattern_text); + + return len; +} + +/* + * evaluate_pattern + * Evaluate expression associated with PATTERN variable vname. current_pos is + * relative row position in a frame (starting from 0). If vname is evaluated + * to true, initial letters associated with vname is appended to + * encode_str. result is out paramater representing the expression evaluation + * result is true of false. + *--------- + * Return values are: + * >=0: the last match absolute row position + * otherwise out of frame. + *--------- + */ +static +int64 +evaluate_pattern(WindowObject winobj, int64 current_pos, + char *vname, StringInfo encoded_str, bool *result) +{ + WindowAggState *winstate = winobj->winstate; + ExprContext *econtext = winstate->ss.ps.ps_ExprContext; + ListCell *lc1, + *lc2, + *lc3; + ExprState *pat; + Datum eval_result; + bool out_of_frame = false; + bool isnull; + TupleTableSlot *slot; + + forthree(lc1, winstate->defineVariableList, + lc2, winstate->defineClauseList, + lc3, winstate->defineInitial) + { + char initial; /* initial letter associated with vname */ + char *name = strVal(lfirst(lc1)); + + if (strcmp(vname, name)) + continue; + + initial = *(strVal(lfirst(lc3))); + + /* set expression to evaluate */ + pat = lfirst(lc2); + + /* get current, previous and next tuples */ + if (!get_slots(winobj, current_pos)) + { + out_of_frame = true; + } + else + { + /* evaluate the expression */ + eval_result = ExecEvalExpr(pat, econtext, &isnull); + if (isnull) + { + /* expression is NULL */ +#ifdef RPR_DEBUG + elog(DEBUG1, "expression for %s is NULL at row: " INT64_FORMAT, + vname, current_pos); +#endif + *result = false; + } + else + { + if (!DatumGetBool(eval_result)) + { + /* expression is false */ +#ifdef RPR_DEBUG + elog(DEBUG1, "expression for %s is false at row: " INT64_FORMAT, + vname, current_pos); +#endif + *result = false; + } + else + { + /* expression is true */ +#ifdef RPR_DEBUG + elog(DEBUG1, "expression for %s is true at row: " INT64_FORMAT, + vname, current_pos); +#endif + appendStringInfoChar(encoded_str, initial); + *result = true; + } + } + + slot = winstate->temp_slot_1; + if (slot != winstate->null_slot) + ExecClearTuple(slot); + slot = winstate->prev_slot; + if (slot != winstate->null_slot) + ExecClearTuple(slot); + slot = winstate->next_slot; + if (slot != winstate->null_slot) + ExecClearTuple(slot); + + break; + } + + if (out_of_frame) + { + *result = false; + return -1; + } + } + return current_pos; +} + +/* + * get_slots + * Get current, previous and next tuples. + * Returns false if current row is out of partition/full frame. + */ +static +bool +get_slots(WindowObject winobj, int64 current_pos) +{ + WindowAggState *winstate = winobj->winstate; + TupleTableSlot *slot; + int ret; + ExprContext *econtext; + + econtext = winstate->ss.ps.ps_ExprContext; + + /* set up current row tuple slot */ + slot = winstate->temp_slot_1; + if (!window_gettupleslot(winobj, current_pos, slot)) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "current row is out of partition at:" INT64_FORMAT, + current_pos); +#endif + return false; + } + ret = row_is_in_frame(winstate, current_pos, slot); + if (ret <= 0) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "current row is out of frame at: " INT64_FORMAT, + current_pos); +#endif + ExecClearTuple(slot); + return false; + } + econtext->ecxt_outertuple = slot; + + /* for PREV */ + if (current_pos > 0) + { + slot = winstate->prev_slot; + if (!window_gettupleslot(winobj, current_pos - 1, slot)) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "previous row is out of partition at: " INT64_FORMAT, + current_pos - 1); +#endif + econtext->ecxt_scantuple = winstate->null_slot; + } + else + { + ret = row_is_in_frame(winstate, current_pos - 1, slot); + if (ret <= 0) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "previous row is out of frame at: " INT64_FORMAT, + current_pos - 1); +#endif + ExecClearTuple(slot); + econtext->ecxt_scantuple = winstate->null_slot; + } + else + { + econtext->ecxt_scantuple = slot; + } + } + } + else + econtext->ecxt_scantuple = winstate->null_slot; + + /* for NEXT */ + slot = winstate->next_slot; + if (!window_gettupleslot(winobj, current_pos + 1, slot)) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "next row is out of partiton at: " INT64_FORMAT, + current_pos + 1); +#endif + econtext->ecxt_innertuple = winstate->null_slot; + } + else + { + ret = row_is_in_frame(winstate, current_pos + 1, slot); + if (ret <= 0) + { +#ifdef RPR_DEBUG + elog(DEBUG1, "next row is out of frame at: " INT64_FORMAT, + current_pos + 1); +#endif + ExecClearTuple(slot); + econtext->ecxt_innertuple = winstate->null_slot; + } + else + econtext->ecxt_innertuple = slot; + } + return true; +} + +/* + * pattern_initial + * Return pattern variable initial character + * matching with pattern variable name vname. + * If not found, return 0. + */ +static +char +pattern_initial(WindowAggState *winstate, char *vname) +{ + char initial; + char *name; + ListCell *lc1, + *lc2; + + forboth(lc1, winstate->defineVariableList, + lc2, winstate->defineInitial) + { + name = strVal(lfirst(lc1)); /* DEFINE variable name */ + initial = *(strVal(lfirst(lc2))); /* DEFINE variable initial */ + + + if (!strcmp(name, vname)) + return initial; /* found */ + } + return 0; +} + +/* + * string_set_init + * Create dynamic set of StringInfo. + */ +static +StringSet * string_set_init(void) +{ +/* Initial allocation size of str_set */ +#define STRING_SET_ALLOC_SIZE 1024 + + StringSet *string_set; + Size set_size; + + string_set = palloc0(sizeof(StringSet)); + string_set->set_index = 0; + set_size = STRING_SET_ALLOC_SIZE; + string_set->str_set = palloc(set_size * sizeof(StringInfo)); + string_set->set_size = set_size; + + return string_set; +} + +/* + * string_set_add + * Add StringInfo str to StringSet string_set. + */ +static +void +string_set_add(StringSet * string_set, StringInfo str) +{ + Size set_size; + + set_size = string_set->set_size; + if (string_set->set_index >= set_size) + { + set_size *= 2; + string_set->str_set = repalloc(string_set->str_set, + set_size * sizeof(StringInfo)); + string_set->set_size = set_size; + } + + string_set->str_set[string_set->set_index++] = str; + + return; +} + +/* + * string_set_get + * Returns StringInfo specified by index. + * If there's no data yet, returns NULL. + */ +static +StringInfo +string_set_get(StringSet * string_set, int index) +{ + /* no data? */ + if (index == 0 && string_set->set_index == 0) + return NULL; + + if (index < 0 || index >= string_set->set_index) + elog(ERROR, "invalid index: %d", index); + + return string_set->str_set[index]; +} + +/* + * string_set_get_size + * Returns the size of StringSet. + */ +static +int +string_set_get_size(StringSet * string_set) +{ + return string_set->set_index; +} + +/* + * string_set_discard + * Discard StringSet. + * All memory including StringSet itself is freed. + */ +static +void +string_set_discard(StringSet * string_set) +{ + int i; + + for (i = 0; i < string_set->set_index; i++) + { + StringInfo str = string_set->str_set[i]; + + if (str) + { + pfree(str->data); + pfree(str); + } + } + pfree(string_set->str_set); + pfree(string_set); +} + +/* + * variable_pos_init + * Create and initialize variable postion structure + */ +static +VariablePos * variable_pos_init(void) +{ + VariablePos *variable_pos; + + variable_pos = palloc(sizeof(VariablePos) * NUM_ALPHABETS); + MemSet(variable_pos, -1, sizeof(VariablePos) * NUM_ALPHABETS); + return variable_pos; +} + +/* + * variable_pos_register + * Register pattern variable whose initial is initial into postion index. + * pos is position of initial. + * If pos is already registered, register it at next empty slot. + */ +static +void +variable_pos_register(VariablePos * variable_pos, char initial, int pos) +{ + int index = initial - 'a'; + int slot; + int i; + + if (pos < 0 || pos > NUM_ALPHABETS) + elog(ERROR, "initial is not valid char: %c", initial); + + for (i = 0; i < NUM_ALPHABETS; i++) + { + slot = variable_pos[index].pos[i]; + if (slot < 0) + { + /* empty slot found */ + variable_pos[index].pos[i] = pos; + return; + } + } + elog(ERROR, "no empty slot for initial: %c", initial); +} + +/* + * variable_pos_compare + * Returns true if initial1 can be followed by initial2 + */ +static +bool +variable_pos_compare(VariablePos * variable_pos, char initial1, char initial2) +{ + int index1, + index2; + int pos1, + pos2; + + for (index1 = 0;; index1++) + { + pos1 = variable_pos_fetch(variable_pos, initial1, index1); + if (pos1 < 0) + break; + + for (index2 = 0;; index2++) + { + pos2 = variable_pos_fetch(variable_pos, initial2, index2); + if (pos2 < 0) + break; + if (pos1 <= pos2) + return true; + } + } + return false; +} + +/* + * variable_pos_fetch + * Fetch position of pattern variable whose initial is initial, and whose index + * is index. If no postion was registered by initial, index, returns -1. + */ +static +int +variable_pos_fetch(VariablePos * variable_pos, char initial, int index) +{ + int pos = initial - 'a'; + + if (pos < 0 || pos > NUM_ALPHABETS) + elog(ERROR, "initial is not valid char: %c", initial); + + if (index < 0 || index > NUM_ALPHABETS) + elog(ERROR, "index is not valid: %d", index); + + return variable_pos[pos].pos[index]; +} + +/* + * variable_pos_discard + * Discard VariablePos + */ +static +void +variable_pos_discard(VariablePos * variable_pos) +{ + pfree(variable_pos); +} diff --git a/src/backend/utils/adt/windowfuncs.c b/src/backend/utils/adt/windowfuncs.c index 473c61569f..92c528d38c 100644 --- a/src/backend/utils/adt/windowfuncs.c +++ b/src/backend/utils/adt/windowfuncs.c @@ -13,6 +13,9 @@ */ #include "postgres.h" +#include "catalog/pg_collation_d.h" +#include "executor/executor.h" +#include "nodes/execnodes.h" #include "nodes/parsenodes.h" #include "nodes/supportnodes.h" #include "utils/fmgrprotos.h" @@ -37,11 +40,19 @@ typedef struct int64 remainder; /* (total rows) % (bucket num) */ } ntile_context; +/* + * rpr process information. + * Used for AFTER MATCH SKIP PAST LAST ROW + */ +typedef struct SkipContext +{ + int64 pos; /* last row absolute position */ +} SkipContext; + static bool rank_up(WindowObject winobj); static Datum leadlag_common(FunctionCallInfo fcinfo, bool forward, bool withoffset, bool withdefault); - /* * utility routine for *_rank functions. */ @@ -674,7 +685,7 @@ window_last_value(PG_FUNCTION_ARGS) bool isnull; result = WinGetFuncArgInFrame(winobj, 0, - 0, WINDOW_SEEK_TAIL, true, + 0, WINDOW_SEEK_TAIL, false, &isnull, NULL); if (isnull) PG_RETURN_NULL(); @@ -714,3 +725,25 @@ window_nth_value(PG_FUNCTION_ARGS) PG_RETURN_DATUM(result); } + +/* + * prev + * Dummy function to invoke RPR's navigation operator "PREV". + * This is *not* a window function. + */ +Datum +window_prev(PG_FUNCTION_ARGS) +{ + PG_RETURN_DATUM(PG_GETARG_DATUM(0)); +} + +/* + * next + * Dummy function to invoke RPR's navigation operation "NEXT". + * This is *not* a window function. + */ +Datum +window_next(PG_FUNCTION_ARGS) +{ + PG_RETURN_DATUM(PG_GETARG_DATUM(0)); +} diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 07023ee61d..b9d171e327 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -10474,6 +10474,12 @@ { oid => '3114', descr => 'fetch the Nth row value', proname => 'nth_value', prokind => 'w', prorettype => 'anyelement', proargtypes => 'anyelement int4', prosrc => 'window_nth_value' }, +{ oid => '6122', descr => 'previous value', + proname => 'prev', provolatile => 's', prorettype => 'anyelement', + proargtypes => 'anyelement', prosrc => 'window_prev' }, +{ oid => '6123', descr => 'next value', + proname => 'next', provolatile => 's', prorettype => 'anyelement', + proargtypes => 'anyelement', prosrc => 'window_next' }, # functions for range types { oid => '3832', descr => 'I/O', diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 1774c56ae3..f2322ace6f 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -2549,6 +2549,11 @@ typedef enum WindowAggStatus * tuples during spool */ } WindowAggStatus; +#define RF_NOT_DETERMINED 0 +#define RF_FRAME_HEAD 1 +#define RF_SKIPPED 2 +#define RF_UNMATCHED 3 + typedef struct WindowAggState { ScanState ss; /* its first field is NodeTag */ @@ -2597,6 +2602,19 @@ typedef struct WindowAggState int64 groupheadpos; /* current row's peer group head position */ int64 grouptailpos; /* " " " " tail position (group end+1) */ + /* these fields are used in Row pattern recognition: */ + RPSkipTo rpSkipTo; /* Row Pattern Skip To type */ + List *patternVariableList; /* list of row pattern variables names + * (list of String) */ + List *patternRegexpList; /* list of row pattern regular expressions + * ('+' or ''. list of String) */ + List *defineVariableList; /* list of row pattern definition + * variables (list of String) */ + List *defineClauseList; /* expression for row pattern definition + * search conditions ExprState list */ + List *defineInitial; /* list of row pattern definition variable + * initials (list of String) */ + MemoryContext partcontext; /* context for partition-lifespan data */ MemoryContext aggcontext; /* shared context for aggregate working data */ MemoryContext curaggcontext; /* current aggregate's working data */ @@ -2633,6 +2651,18 @@ typedef struct WindowAggState TupleTableSlot *agg_row_slot; TupleTableSlot *temp_slot_1; TupleTableSlot *temp_slot_2; + + /* temporary slots for RPR */ + TupleTableSlot *prev_slot; /* PREV row navigation operator */ + TupleTableSlot *next_slot; /* NEXT row navigation operator */ + TupleTableSlot *null_slot; /* all NULL slot */ + + /* + * Each byte corresponds to a row positioned at absolute its pos in + * partition. See above definition for RF_* + */ + char *reduced_frame_map; + int64 alloc_sz; /* size of the map */ } WindowAggState; /* ---------------- -- 2.25.1 ----Next_Part(Thu_Mar_28_19_59_25_2024_076)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v15-0006-Row-pattern-recognition-patch-docs.patch" ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/3] Remove unnecessary volatile qualifiers. @ 2026-02-18 16:31 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-02-18 16:31 UTC (permalink / raw) --- src/backend/replication/syncrep.c | 19 ++++++++----------- src/backend/storage/ipc/procsignal.c | 4 ++-- src/backend/storage/lmgr/lock.c | 2 +- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 5 files changed, 14 insertions(+), 17 deletions(-) diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index 7ea6001e9ad..045fd35786a 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -473,7 +473,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -548,19 +547,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -767,8 +766,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -905,7 +903,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -920,7 +917,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 5d33559926a..97791f979ef 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -283,7 +283,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -394,7 +394,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index e1168ad3837..718de1b5e98 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -309,7 +309,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; /* diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 579e5933d28..a1ec13d66b9 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -36,7 +36,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -256,7 +256,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index 368e4f3f234..14972f7e7cd 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -50,7 +50,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --J5cpktPts8HkLShw Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename=v1-0002-Remove-SpinLockFree-and-S_LOCK_FREE.patch ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* remove unnecessary volatile qualifiers @ 2026-06-30 21:47 Nathan Bossart <nathandbossart@gmail.com> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <hlinnaka@iki.fi> 0 siblings, 1 reply; 653+ messages in thread From: Nathan Bossart @ 2026-06-30 21:47 UTC (permalink / raw) To: pgsql-hackers I looked into some of these earlier [0], but ended up leaving them alone at the time. Here is a new patch that removes all of the volatile markers in the tree that seemed obviously unnecessary to me. [0] https://postgr.es/m/aZX2oUcKf7IzHnnK%40nathan -- nathan ^ permalink raw reply [nested|flat] 653+ messages in thread
* Re: remove unnecessary volatile qualifiers 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> @ 2026-07-06 11:58 ` Heikki Linnakangas <hlinnaka@iki.fi> 2026-07-06 15:47 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 0 siblings, 1 reply; 653+ messages in thread From: Heikki Linnakangas @ 2026-07-06 11:58 UTC (permalink / raw) To: Nathan Bossart <nathandbossart@gmail.com>; pgsql-hackers On 01/07/2026 00:47, Nathan Bossart wrote: > I looked into some of these earlier [0], but ended up leaving them alone at > the time. Here is a new patch that removes all of the volatile markers in > the tree that seemed obviously unnecessary to me. Thanks! > --- a/src/backend/access/transam/clog.c > +++ b/src/backend/access/transam/clog.c > @@ -450,7 +450,7 @@ static bool > TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, > XLogRecPtr lsn, int64 pageno) > { > - volatile PROC_HDR *procglobal = ProcGlobal; > + PROC_HDR *procglobal = ProcGlobal; > PGPROC *proc = MyProc; > uint32 nextidx; > uint32 wakeidx; You might want to get rid of the local variable altogether and just refer to ProcGlobal directly.. > @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) > { > uint64 local_gen; > uint64 shared_gen; > - volatile uint32 flags; > + uint32 flags; > > Assert(MyProcSignalSlot); > Are you sure about this one? 'flags' is used in the PG_TRY/CATCH block that follows. It is modified in the PG_TRY(), here: > > /* > * To avoid an infinite loop, we must always unset the bit in > * flags. > */ > BARRIER_CLEAR_BIT(flags, type); and read later in the PG_CATCH() block. The rest looks OK to me. - Heikki ^ permalink raw reply [nested|flat] 653+ messages in thread
* Re: remove unnecessary volatile qualifiers 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <hlinnaka@iki.fi> @ 2026-07-06 15:47 ` Nathan Bossart <nathandbossart@gmail.com> 2026-07-07 16:03 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 0 siblings, 1 reply; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:47 UTC (permalink / raw) To: Heikki Linnakangas <hlinnaka@iki.fi>; +Cc: pgsql-hackers On Mon, Jul 06, 2026 at 02:58:12PM +0300, Heikki Linnakangas wrote: > On 01/07/2026 00:47, Nathan Bossart wrote: >> I looked into some of these earlier [0], but ended up leaving them alone at >> the time. Here is a new patch that removes all of the volatile markers in >> the tree that seemed obviously unnecessary to me. > > Thanks! Thanks for reviewing. >> --- a/src/backend/access/transam/clog.c >> +++ b/src/backend/access/transam/clog.c >> @@ -450,7 +450,7 @@ static bool >> TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, >> XLogRecPtr lsn, int64 pageno) >> { >> - volatile PROC_HDR *procglobal = ProcGlobal; >> + PROC_HDR *procglobal = ProcGlobal; >> PGPROC *proc = MyProc; >> uint32 nextidx; >> uint32 wakeidx; > > You might want to get rid of the local variable altogether and just refer to > ProcGlobal directly.. Done. >> @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) >> { >> uint64 local_gen; >> uint64 shared_gen; >> - volatile uint32 flags; >> + uint32 flags; >> Assert(MyProcSignalSlot); > > Are you sure about this one? 'flags' is used in the PG_TRY/CATCH block that > follows. It is modified in the PG_TRY(), here: > >> >> /* >> * To avoid an infinite loop, we must always unset the bit in >> * flags. >> */ >> BARRIER_CLEAR_BIT(flags, type); > > and read later in the PG_CATCH() block. Whoops. You are right. I reverted this part. -- nathan ^ permalink raw reply [nested|flat] 653+ messages in thread
* Re: remove unnecessary volatile qualifiers 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <hlinnaka@iki.fi> 2026-07-06 15:47 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> @ 2026-07-07 16:03 ` Nathan Bossart <nathandbossart@gmail.com> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-07 16:03 UTC (permalink / raw) To: Heikki Linnakangas <hlinnaka@iki.fi>; +Cc: pgsql-hackers Committed. -- nathan ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 653+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 653+ messages in thread
end of thread, other threads:[~2026-07-07 16:03 UTC | newest] Thread overview: 653+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2023-02-25 21:39 [PATCH v2] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState Andres Freund <andres@anarazel.de> 2023-02-25 21:39 [PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState Andres Freund <andres@anarazel.de> 2024-03-28 10:30 [PATCH v15 5/8] Row pattern recognition patch (executor). Tatsuo Ishii <ishii@postgresql.org> 2026-02-18 16:31 [PATCH v1 1/3] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <hlinnaka@iki.fi> 2026-07-06 15:47 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 2026-07-07 16:03 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <nathandbossart@gmail.com> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <nathan@postgresql.org>
This inbox is served by agora; see mirroring instructions for how to clone and mirror all data and code used for this inbox